Various methods are known for producing aluminocarbonate compounds. For example, sodium aluminocarbonate, also known as dihydroxy aluminum sodium carbonate, may be made by a carbonate (Na.sub.2 CO.sub.3)-alum (Al.sub.2 (SO.sub.4).sub.3) reaction which comprises neutralizing sodium carbonate with clarified alum to a pH of 7 to 8. This process, however, produces a liquor containing Na.sub.2 SO.sub.4 which requires further processing before disposal.
The German Patent No. 19,784 to Lowig discloses a method for producing sodium or potassium aluminocarbonates by simultaneously adding gaseous carbon dioxide and a sodium or potassium aluminate solution to a solution of sodium or potassium bicarbonate. Similarly, U.S. Pat. Nos. 2,783,124 and 2,783,127 to Grote disclose methods for the preparation of dihydroxy aluminum alkali metal or ammonium carbonate compounds by reacting an aluminum compound with the corresponding bicarbonate compound in the presence of water. Additionally, U.S. Pat. No. 2,783,179 to Grote discloses methods for producing isomeric aluminum hydroxy sodium carbonate compounds by the reaction between aluminum alkoxide and sodium carbonate in an aqueous medium wherein a copious quantity of carbon dioxide is bubbled through the solution and continued for the duration of the preparation.
U.S. Pat. No. 3,539,306 to Kumura et al discloses the preparation of an aluminum magnesium carbonate compound which comprises mixing an aluminum component with a magnesium component in an aqueous medium in the presence of carbonate ion at a pH of at least 8 and thereafter recovering the resultant precipitate. The required presence of carbonate ion in the reaction system can be effected by blowing carbon dioxide gas into the system or by addition of a carbonate. U.S. Pat. No. 2,958,626 to Schenck et al discloses methods for preparing aluminum magnesium carbonate compounds by mixing aluminum hydroxide or a derivative thereof with a solution containing magnesium bicarbonate in the presence of an excess of carbon dioxide. A steady stream of carbon dioxide is allowed to flow into the reaction solution through a gas dispersion tube.
U.S. Pat. No. 3,975,503 to Hauschild et al discloses a method for producing alkali carbonate wherein an alkali carbonate and alkali hydroxide containing solution stream is charged into a reaction chamber containing a carbon dioxide gas at a temperature from 150-750.degree. C.
The known methods for preparing aluminocarbonate compounds have various disadvantages including low efficiency of carbon dioxide utilization, production of sulfate-containing byproducts and production of non-amorphous crystalline aluminocarbonate products.